WHAT IS THCb

THCb (tetrahydrocannabutol) is a phytocannabinoid identified in cannabis in 2019, alongside the discovery of THCp. Both have modified alkyl side chains compared to standard Δ9 THC. THCb has a 4-carbon butyl chain (Δ9 has a 5-carbon pentyl chain).

The shorter side chain results in a different shape that fits CB1 receptors more tightly than standard Δ9. Preclinical research shows THCb binds CB1 with higher affinity than Δ9 — though not as dramatically higher as THCp’s 30× affinity.

THCb is present in cannabis at very low concentrations (under 0.05% in most cultivars). Commercial THCb products are typically synthesized rather than extracted, similar to other rare cannabinoids.

EFFECTS + STATUS

THCb has limited human research. Preclinical animal studies show cannabis-like effects. Commercial THCb products (typically vape carts and gummies) report subjective experiences similar to Δ9 with potentially slightly different character.

Pricing is high due to the rarity. Most THCb products are blends with other hemp cannabinoids (THCp, HHC, Δ8) rather than pure THCb.

Legal status: contested gray zone, similar to other synthesized hemp cannabinoids. Federal Schedule I scrutiny applies to synthetic THC analogues.